Various kinds of electronic devices, e.g., smartphones, tablet computers, or digital cameras, may be equipped with increasingly sophisticated imaging functionalities. Such imaging functionalities for example include capturing of high dynamic range (HDR) still images or videos. Here, the term “HDR” means that a dynamic range concerning an ability to resolve features in regions of low luminosity and high luminosity of an imaged scene is increased as compared to conventionally captured images. This means that a certain contrast level allowing for resolving image details may be attained both in image regions of low luminosity and image regions of high luminosity, avoiding contrast limiting effects of under exposure or over exposure.
A typical way of capturing HDR images is to utilize an imaging sensor for capturing multiple (typically two or three) full resolution images in a row, using different exposure times, and then combine these images to the HDR image. However, due to the time offset between capturing the different images, the combined HDR image may suffer from blurring or ghosting of moving objects in the imaged scene and/or from overall blurring due to movement of the imaging sensor while capturing the different images. While such undesirable effects may in principle be reduced by decreasing the time offset between capturing the different images, such decrease of the time offset may often be limited by the utilized imaging sensor and associated image processing electronics. For example, detecting the outputs of all pixels of the imaging sensor and processing these outputs to obtain the desired image data may limit the time offset. In typical devices, the minimum supported time offset may be in the range 20 to 50 ms.
Accordingly, there is a need for techniques which allow for efficiently capturing high dynamic range images.